Lifting-surface for flying-machines.



G. H. BURLEIGH.

LIFTING SURFACE FOR FLYING MACHINES.

APPLIGATION FILED APR. 27, 1911.

Patented Jan. 13, 1914.

, Ema/17%? MAW wild Cab/w W y h I 47 xiFfi i/ izjr till CHARLES H.BURLEIGH, OF SOUTH BERWICK, MAINE.

LIFTING-SURFAGE FOR FLYING-MACHINES.

Specification of Letters Patent.

llateni ed Jan. l3, NW4.

Application filed April 27, 1911. Serial No. 623,557.

To all whom it mag concern:

Be it known that 1, CHARLES H. Bun- LEIGH, a citizen of the UnitedStates. residing at South Berwick, county of York, State of Maine, haveinvented a certain new and useful lmprovement in Lifting-Surfaces forFlying-Machines, of which the following is a specification, referencebeing had therein to the accompanying drawings.

.My invention has for its object a lifting surface for flying machines,especially of the heavier than air type, but which shall be applicableto any form of flying machine which is supported in whole or in part asaresult of movement through the air.

The invention is a very broad one, and may be embodied in a greatvariety of forms. I have therefore shown only my preferred form, but Ido not limit myself to the particular form shown.

As is well known, when a solid object moves rapidly through the airthere is produced at the rear of the object a rarefaction of the airwhich is dependent in intensity on the rapidity of movement of theobject and the shape of the rear end. in the case of a jacketed bullet,a substantial yacuum is formed directly behind the bullet. if the steeljacket of the bullet be cut away on one side, and if the bullet be shotthrough the air without being caused to revolve about its longitudinalaxis, it will be found that the bullet will follow a curved path throughthe air by reason of the fact that there is an uncompensated pressure onthe outside of the steel jacket resulting from the partial vacuum formedbehind the end of the bullet. My present invention utilizes thisprinciple for the purpose of supporting the lifting surface of anaeroplane in the air.

ll accomplish my object by providing a surface of the. flying machinewith 'a series of vacuum-forming depressions, each of which hasasubstantially vertical or sloping front wall and a gently sloping rearwall. The movement of the lifting surface through theair causes ararefaction of the air in the pocket or hollow. back of the substantialvertical rear wall so that there is an unbalanced force operating uponthe under side of the plane and tending to lift it.

The plane embodying my invention and having the vacuum depressionstherein may be made in a variety of ways, a convenient method being toform a light frame of paral lel bars properly stayed, and passingsuitable fabric over the parallel rods in the manner shown in thedrawings, thus making a light and eflicie it lifting surface.

The invention will be fully understood from the following descriptiontaken in connection with the accompanying drawings and the novelfeatures thereof are pointed out and clearly defined in the claim at theclose of the specification.

Referring to the drawings, Figure 1 is a plan view of the planeembodying my invention. Fig. 2 is a longitudinal section thereof.

The lifting surface in the form shown in the drawings consists ofa'frame made up of a series of parallel rods A, A, which may be securedtogether and braced as desired. its the method of securing the parts ofthe frame together, and properly bracing the same forms no part of myinvention it is not shown in the drawings and l will not describe ithere. The under side of the plane is covered with a piece of properlystretched smooth fabric of some suitable kind, which is flat orsubstantially flat. In the upper surface there are formed a series oftransverse grooves or depressions 03 by passing asuitable web of clothover and under the transverse rods it A of the frame.

it will be seen that when the lifting plane progresses through the airin the direction of the large arrows in Figs. land 2 a partial vacuum orrarefaction of the air is formed in each of the depressions (i, lhe airon the upper surface of the plane may be considered as traveling in thedirection of the small arrows a and the particles of air in thedepressions (Z tend to be left behind by the movement of the surfacethrough the air and are carried away by the rush of air thus forming ararefaction of the air in the depressions 05,. a3. After the vacuum orrare faction has been formed in the depressions cl, at there is anuncompensated upward pressure on the under surface of the plane,

as indicated by the small arrows 5, b. This uncompensated pressureon-the under surface of the plane tends to lift the aeroplane. It willbe seen that with a large surface a very slight rarefaction in thedepressions will give the plane a large lifting power.

The grooves or "depressions may probably be made with the frontv wall ofthe depression at a considerable angle from the vertical and sloping ineither direction, and this angle may be varied according to the speed atwhich the lifting surface moves through 5 the air, but this is a matterof design as my invention covers any vacuum forming depression locatedin any portion of any part of a flying machine. While I have shown thevacuum forming depressions as applied to the upper surface of a planefor a flying machine I conceive it possible to use vacuum formingdepressions in other parts of a flying machine as for instance thefloor.

What I claim is? The surface for flying machines having a fiatundersurface and Vacuum forming depressions in the upper surface, saidvacuum forming depression being formed by stretching cloth over parallelbars.

In testimony whereof I afiix' my signature in presence of tWo Witnesses.

CHARLES BURLEIGH.

Witnesses:

WILLIAM F. HoncDoN, JOHN M. BURLEIGH.

